This invention relates to grommets and more particularly to grommets for sealing a line or cable passing through an opening in a vehicle bulkhead or panel.
In the securing of electrical wires, cables, hydraulic lines, and other elongated elements, through vehicle bulkhead or panel openings, their support grommets are subjected to vibration pull-out forces and the like. Also, the elongated elements must allow for low profile routing wherein the elements are bent at steep angles on either side of the panel. As a result it has long been a problem to prevent the grommets from unseating and developing leaks that allow the passage of air, water and foreign matter through the vehicle walls. The U.S. Pat. No. 2,897,533 issued Aug.6, 1959 to Bull et al and U.S. Pat. No. 4,289,924 issued to Pearce, Jr. et al are examples of prior art grommets designed to be sealing mounted within a panel opening.
Still another common problem in vehicle assembly wiring attachment is to provide a grommet that allows quick installation by hand without the necessity for using tools or separate fastening elements. The U.S. Pat. No. 4,487,998 issued Dec. 11, 1984 to Pegram is an example of a grommet employing a release tool.
Special requirements must be met when designing an expandable and applied flexible grommet intended for use in automotive wiring harnesses to prevent leakage around the perimeter or through the center of the grommet resulting from suction or pressure differential between the inside and outside of the vehicle body. An example of a prior art grommet designed to snugly surround an elongated element and at the same time to permit controlled axial and radial movement is shown in U.S. Pat. No. 1,800,578 issued April 14, 1931 to Webb.
These and other disadvantages in prior devices have necessitated the maintenance of an inventory of different grommets for use with cables of varying sizes and applications. It has been the practice in the automotive industry to employ molded-on vinyl plastic grommets. Such grommets have numerous problems including leakage at their mold parting lines, improper molding techniques, material set, etc. An example of a molded plastic grommet is disclosed in U.S. Pat. No. 4,081,879 issued Apr. 4, 1978 to Rubright.